A. Field of the Invention
The invention relates to a method, system, and apparatus for controlling, acquiring and processing digital radioscopic image data, and in particular to a method, system and apparatus for correcting digital x-ray images and converting acquired digital radioscopic x-ray image data to a format readable by a mobile C-arm x-ray imaging system that is used to examine a patient's soft tissue and/or bone structure.
B. Description of the Related Art
Medical imaging is a specialty that uses radiation, such as gamma rays, x-rays, high-frequency sound waves, magnetic fields, neutrons, or charged particles to produce images of internal body structures. In diagnostic radiology, radiation is used to detect and diagnose disease, while in interventional radiology, radiation is used to treat disease and bodily abnormalities.
Radiography is the technique of producing an image of any opaque specimen by the penetration of radiation, such as gamma rays, x-rays, neutrons, or charged particles. When a beam of radiation is transmitted through any heterogeneous object, the radiation is differentially absorbed depending upon varying object thickness, density, and chemical composition. The radiation emergent from the object forms a radiographic image, which may then be realized on an image detection medium, such as photographic film directly or by using a phosphor to first create a light image. Radiography is a non-destructive technique of testing a gross internal structure of an object, and is conventionally used in medical and industrial applications. Radiography is used to non-destructively detect medical conditions such as tuberculosis and bone fractures, to diagnose vascular conditions, as well as manufacturing imperfections in materials such as cracks, voids, and porosities.
X-ray radiography finds particular usefulness in medical and industrial applications. X-rays are a form of electromagnetic radiation, and were accidentally discovered in 1895 by Wilhelm Conrad Roentgen. X-rays are alternately referred to as roentgen rays. In circa 1895, Roentgen found that x-rays propagate through an internal object such as a hand and expose photographic film, thereby revealing an internal structure. X-rays exhibit different properties than visible light rays, and were designated by Roentgen as “x-rays,” with “x” referring to the unknown. For example, x-rays are not focused with a traditional optical light lens, but rather use sophisticated focusing techniques. Today, x-rays are categorized as electromagnetic radiation having a frequency range extending between 2.4×1016 Hz to 5×1019 Hz. Most x-rays have a wavelength smaller than an atom and therefore interact with matter in a granular fashion, that is, like bullets of photon energy. X-rays are absorbed by materials according to the exponential absorption law
where IO is the initialIxIoe−μx=Ioe−(μ/ρ)ρx  (1.0)intensity of the x-ray beam; Ix is the intensity after passage through an object, the object having a thickness x, density ρ, linear absorption coefficient μ, and mass absorption coefficient μ/ρ.
X-rays are formed through celestial phenomenon, such as internal reactions of stars and quasars, and through electronic x-ray generation devices, such as x-ray tubes. X-ray tubes generally produce x-rays by accelerating a charged particle, such as an electron, through an electrostatic field and then suddenly stopping the x-ray through collision with a solid target. This collision ionizes the solid target by transporting closely held electrons to a higher energy state. As the electrons in the solid target return to their original energy state, x-rays are produced. X-rays are produced within x-ray tubes by accelerating electrons in a vacuum from a cathode toward an anode, with or without particle beam shaping and accelerating through placement of electrodes.
The electronic detection of x-rays is generally referred to as electronic radiography or radioscopy. Prior to electronic detection, radiographic images were captured on photographic film or displayed on a fluorescent screen. Real time visual observation of x-rays on a fluorescent screen is referred to as fluoroscopy. However, as early as the 1930s photo-multiplier tubes (a form of vacuum tube) were developed to produce an electrical signal in response to received light. Photo-multiplier tubes generally respond well to optical range light rays and are therefore often optically coupled with a scintillating material to detect non-optical electro-magnetic radiation. The scintillating material converts non-optical radiation, such as gamma rays (emitted by radio-active isotopes used in nuclear medicine) and x-rays into optical radiation. Beginning circa 1980, photo-multiplier/scintillator detectors are generally being replaced by amorphous silicon based photo-cells.
Radioscopy includes one shot x-ray detection, also known as fluorography, and multiple shot x-ray detection, also known as fluoroscopy. Radio-mammography is a form of radioscopy in which the breast is vigorously compressed prior to exposure to maximize detail and minimize radiation exposure. Computed tomography (“CT”), also called computed axial tomography (“CAT”), is a form of radioscopy in which an x-ray tube is rotated around the body while emitting a narrow x-ray beam. The received x-ray beam information is then combined in a computer to produce a two or three dimensional anatomic medical image. Magnetic resonance imaging (“MRI”) is a diagnostic procedure in which a high strength magnet aligns the spin of nuclei within cells of a body, such that each nuclei acts like a radio, both receiving and transmitting radio signals. External radio frequency signals are then applied to the body to disturb the spinning cellular nuclei. After the radio signal is stopped, the nuclei realign with the applied magnetic field while emitting faint radio signals. These faint radio signals correspond to different body tissues and are detected to produce an anatomical image.
Radioscopy and related medical diagnostic imaging technologies use precision control over penetrating radiation and well as precision timing for detection and processing of resultant image data. Medical diagnostic imaging generally acquires and controls a very large amount of image data, which in turn is communicated to computer processing equipment at a very high data rate. To provide control over the generation, detection, and processing of medical diagnostic imaging, computer workstations employ the use of a real time operating system (“RTOS”) to control operation.
The GE OEC Series 9800 is a mobile device used to examine a patient's body for any internal injuries to the patient's soft tissue and bones. In its current configuration, at one end of the C-arm there is provided an x-ray generation unit, and at the other end of the C-arm there is provided an x-ray detector. A patient is placed on a cart in an area between the respective ends of the C-arm, and x-rays are passed through portions of the patient's body in order to check for any internal injuries. Each pixel of the x-ray detector used with the GE OEC Series 9800 outputs an x-ray received signal level as an electrical signal to a Charged-Coupled Device (CCD) array, which outputs a respective light signal level. The light signals from the plurality of pixels of the CCD array are focused onto a respective pixel region on a small CCD panel (e.g., 1 inch by 1 inch panel), and that information is provided to a work station. Based on the information received, the work station outputs an image for a user, such as a doctor, to review. Also, based on the image received, the work station can control the amount of x-ray power output by the x-ray generator, and the reception characteristics of the x-ray detector.
The current GE OEC Series 9800 work station receives information from the CCD array in a particular format, with horizontal syncs, vertical syncs, vertical blanks, horizontal blanks, etc. (which is similar to a traditional TV format, or an analog image format such as that used by a monitor for a personal computer). If data is received in any different format, the work station cannot properly process the data.
There is a need to provide an interface that allows x-ray detectors which output x-ray detection signals in a different format to be able to communicate with the GE OEC Series 9800. Also, there is a need to take data in other formats and provide a synchronous stream of digital data in a traditional format with H syncs and V syncs.